Core trays

ABSTRACT

The invention relates to a plastic drill core tray of the type having a plurality of longitudinally extending channels disposed in a side by side relationship which are dished in cross-section to contain a drill core. The effective contained angle of the cross-section at the dished bottom of the channels is greater than 90*. The plastic tray is reinforced with elongated metal reinforcing ribs having a U-shaped cross-section. The ribs are adhered to adjacent longitudinally extending marginal areas of adjacent channels to provide longitudinally extending reinforcing means, and the contained angle of the cross-section of the tray at the adjacent longitudinally extending areas is less than 90*.

[ 1 Jan. 22, 1974 1 1 CORE TRAYS Carl M. Smith, Weston, Ontario, Canada[73] Assignee: Schlegel Company Canada Limited,

Oakville, Ontario, Canada [22] Filed: Oct. 8, 1971 [21] Appl. No.:187,757

Related U.S. Application Data [63] Continuation-impart of Ser. No.42,770, June 21,

1970, abandoned.

[75] Inventor:

[52] US. Cl 211/60 A, 206/65 A, 220/23.8, 264/92, 264/275 [51] Int. Cl.A471 7/00 [58] Field of Search 425/123, 127, 126; 264/92; 206/65 A, 67,77, .84, 43, 17.1, 17.5; 220/71 U, 71 S, 23.8; 62/359; 211/60 A, 60 M,60

2,896,809 7/1959 Metzger 220/23.8 X 2,927,71 1 3/1960 Naggiar 3,476,25911/1969 Price 211/13 X FORElGN PATENTS OR APPLlCATlONS 531,345 10/1956Canada 206/65 A 1,060,599 11/1953 France 220/22 Primary ExaminerRoy D.Frazier Assistant Examiner-Abraham Frankel Attorney, Agent, or FirmAlexander & Dowell 5 7] ABSTRACT The invention relates to a plasticdrill core tray of the type having a plurality of longitudinallyextending channels disposed in a side by side relationship which aredished in cross-section to contain a drill core. The effective containedangle of the cross-section at the dished bottom of the channels isgreater than 90. The plastic tray is reinforced with elongated metalreinforcing ribs having a U-shaped cross-section. The ribs are adheredto adjacent longitudinally extending marginal areas of adjacent channelsto provide longitudinally extending reinforcing means, and the containedangle of the cross-section of the tray at the adjacent longitudinallyextending areas is less than 90.

2 Claims, 7 Drawing Figures PMENTEDJANZZW 3,786,932

SHEET 1 [1F 2 VAC CORE TRAYS.

FIELD. OF INVENTION This invention relates to. the manufacture ofplastic trays for storing drill cores and the like and is. acontinuation-in-part of application Ser. No. 42770, field June 21, 1970,and now abandoned.

PRIOR ART The drill core trays which. are presently in use in themineral exploration industry are generally made from wood and have asurface formed to provide a plurality of longitudinally extendingchannels to receive the core samples. To ensure that the wooden traysare sufficiently strong to support drill cores it is necessary to makethem of a substantial. thickness, with the result that they are ratherheavy and difficult to ship from one exploration drill site to another.While it is well known to make trays from plastic material theconventional vacuum formed tray is quite unsuitable for use as a drillcore storage tray. A plastic tray having the strength required tosupport and store drill cores would have to be made from a very thickplastic material in order to have sufficient strength. A tray made froma very thick plastic material would be very expensive and would offerlittle advantage over the wooden construction presently known.

SUMMARY By constructing a tray from asheet of plastic material andarranging the core receiving channels close to one another, it has beenfound that the contained angle between the marginal areas of adjacentchannels provides an area which may be readily reinforced to provide thestrong lightweight tray. The contained angle between the marginal areasof adjacent channels may be arranged to be less than 90 such that it ispossible to insert a lightweight metal reinforcing rib between themarginal edges of the channel to reinforce the tray. The reinforced trayis inexpensive to manufacture using a vacuum forming process and it islight in weight.

According to an embodiment of the present invention, a storage traycomprises a plastic bottom formed of a plurality of parallellongitudinally extending channels, each having a dished cross-sectionwith a contained angle at the bottom of more than 90. Each channelmerges with an adjacent channel at the longitudinal edge. Transversereinforcing ribs are adhered and complementary with the bottom andlocated at longitudinally spaced intervals. The tray is also reinforcedby elongated metal reinforcing ribs which have a U cross-section. Thearms of the U section are adhered to adjacent longitudinally extendingmarginal areas of adjacent channels.

PREFERRED EMBODIMENT The invention will be more clearly understood withreference to the following detailed specification read in conjunctionwith the drawings, wherein:

FIG. I is a pictorial view of a tray according toan embodiment of thepresent invention;

FIG. 2 is a cross-sectional view of a mould showing a first step in theforming process;

FIG. 3 is a sectional view similar to FIG. 2 showing a second stage inthe forming process;

FIG. 4 is a pictorial view of a mould illustrating the manner in whichthe reinforcing ribs are located prior to its vacuum forming of thetray;

- FIG. 5 is an enlarged portion of a cross-section taken along the line55 in FIG. 4;

FIG. 6-is a cross-section taken through a longitudinal reinforcing rib;and

FIG. 7 is a bottom perspective view of an alternative construction.

The numeral 10 refers generally to a tray according to this invention.It is made from a rigid vinyl sheet of plastic 12 having a thickness ofabout 0.040 inches. The tray 10 is formed with a plurality of parallellongitudinally extending channels 14, each having a dished cross-sectionadapted to receive contents in use. Adjacent channels merge alonglongitudinal edges.

Reinforcing ribs 16 of U cross-section are adhered to adjacentlongitudinally extending marginal areas of adjacent channels 14. Ribs 16are of steel about 0.031 inches thick (22 gauge). Transverse reinforcingribs 18 are formed to complement the underside of the tray 12.

The advantage of this structure is derived from the combination of aplastic channelled bottom and longitudinal and transverse steelreinforcing members, the longitudinal reinforcing members being at themarginal areas where adjacent channels meet. The contained angle at thepoint where adjacent channels meet is important because it affects thelongitudinal stiffness of the adhered longitudinal reinforcing memberfor a given gauge. These reinforcing members must be light in weight toachieve the overall objective of an inexpensive portable yet strongtray. The effective contained angle A of the U-shaped cross-section ofthe ribs shouldv not be greater than The preferred range is 45, plus orminus 10. If the angle is larger, the reinforcing member will lose muchof its stiffness longitudinally of itself and its effectiveness isreduced as a reinforcing member. The effective contained angle B of thecross-section at the dished bottom of the channels is greater than 90 asindicated in FIG. 5. It is important that the reinforcing ribs 16 be atthe marginal areas where adjacent corrugations meet to achieve theobjective of lightness and economy. If the objective was to provideconstruction strength at any cost, the reinforcement could effectivelybe made at the dished bottoms of the channels, but the contained angleof the dished'section is much larger than it is where the marginalportions of adjacent channel walls merge and for a given strength, moresteel would be necessary.

The tray is preferably made by a vacuum forming process on a mould 24illustrated in FIG. 4 of the drawings. The mould 24 has a foraminousmoulding surface that is complementary to the underside of the tray tobe formed, and in use one first locates the transverse ribs 18 in therecesses provided in the mould as illustrated at the right-hand end ofFIG. 4 of the drawing. Following this, the longitudinally extending ribs16 are placed over the peaks of the mould and the peaks 19 of the ribs18. It will be noted that the peaks 19 of the ribs 18 are recessed toaccommodate the longitudinal ribs 16. The ribs 16 and 18 are precoatedwith an adhesive of a type, which when heat activated, will form a bondwith the plastic sheet 12. The rigid vinyl sheet 12 is then clamped in aposition overlying the mould in the position shown in FIG. 2 of thedrawings. The vinyl sheet is then heated to render it formable and theair is withdrawn from the mould by way of the platen illustrated inFIGS. 2 and 3 of the drawings. By applying a vacuum, the heated sheet 12is drawn into the mould to conform with the upper surface of the mouldas the interior of the mould is evacuated of air. Activation of theadhesive may require preheating of the steel.

FIG. 5 of the drawings shows the cross-sectional structure of areinforced portion of the tray, from which it will be seen that thedished configuration of the channels is not affected by the reinforcingribs 16 or 18, the rib 18 being formed with a recessed portion 19 at thepeaks thereof to accommodate the longitudinal rib 16.

As indicated in FIG. 6 of the drawings, the contained angle A of theU-shaped rib is preferably in the range of 45, plus or minus l0.

The tray illustrated in FIG. 1 of the drawings has a length of about 60inches and a width of about 7 /4 inches and it is particularly suitablefor storing drill cores in the mineral exploration industry.

The materials specifications are by way of example only and it will beapparent that reinforcing members of different thickness and plasticsheets of different thickness and proportions are possible within thescope of the invention.

It has been found that the transverse reinforcing ribs 18 are notnecessary on a tray having five longitudinally extending channels with atotal width of about 9 inches and length of about 4 feet or less. It hasalso been found that with a tray in the order of 4 feet or less long itis not necessary that the elongated metal reinforcing ribs 16 shouldextend for the full length of each channel. The reinforcing ribs 16 canextend for less than the full length of their respective adjacentchannels but any cross-section of the tray through the channels mustinclude at least two of the metal reinforcing ribs. A practicalarrangement for a 4 foot long tray has been illustrated in FIG. 7 whichshows a tray from the underside from which the longitudinally extendingreinforcing ribs 16 are visible. It will be noted that the elongatedmetal reinforcing ribs 16 do not extend for the full length of theadjacent channels that they reinforce. The outside ribs start from anend of the tray and discontinue. The end portions of the two inside ribsare coextensive with the end portions of the outside ribs. It will benoted that any cross section of the tray will include at least two metalreinforcing ribs and that at least one end portion of each rib isco-extensive with an end portion only of its adjacent rib. It isconceivable that with more than five channels there would be more thantwo co-extensive ribs at the center locations in which case theforegoing limitation would not be true of the center reinforcing rib.

It should also be noted that for use under extreme climatic conditionssuch as lower than 40 below zero it may be desirable to additionallyrivet the reinforcing members to the plastic in order to avoidseparation under shock conditions.

What I claim as my invention is:

1. A tray comprising a plastic bottom formed with a plurality ofparallel longitudinally extending channels, each having a dishedcross-section with side walls that make a contained angle at the bottomof more than and each merging with an adjacent channel at a longitudinaledge, and elongated metal reinforcing ribs each having a Ucross-section, the arms of the U being adhered to adjacentlongitudinally extending marginal areas of adjacent channels, thecontained angle of the cross-section of said tray at said adjacentlongitudinally extending areas being less than 90, and transversereinforcing ribs adhered to and complementary to the cross-sectionalshape of the said bottom.

2. A tray comprising, a plastic bottom formed with a plurality ofparallel longitudinally extending channels, each having a dishedcross-section with side walls that make a contained angle at the bottomof more than 90 and each merging with an adjacent channel at alongitudinal edge, and elongated metal reinforcing ribs each having a Ucross-section, the arms of the U being adhered to adjacentlongitudinally extending marginal areas of adjacent channels, thecontained angle of the cross-section of said tray at said adjacentlongitudinally extending areas being less than 90, said contained angleof a cross-section of said tray at the longitudinally extending areasbeing 45, plus or minus 10, and transverse reinforcing ribs adhered toand complementary to the cross-sectional shape of said bottom.

1. A tray comprising a plastic bottom formed with a plurality ofparallel longitudinally extending channels, each having a dishedcross-section with side walls that make a contained angle at the bottomof more than 90* and each merging with an adjacent channel at alongitudinal edge, and elongated metal reinforcing ribs each having a Ucross-section, the arms of the U being adhered to adjacentlongitudinally extending marginal areas of adjacent channels, thecontained angle of the cross-section of said tray at said adjacentlongitudinally extending areas being less than 90*, and transversereinforcing ribs adhered to and complementary to the cross-sectionalshape of the said bottom.
 2. A traY comprising, a plastic bottom formedwith a plurality of parallel longitudinally extending channels, eachhaving a dished cross-section with side walls that make a containedangle at the bottom of more than 90* and each merging with an adjacentchannel at a longitudinal edge, and elongated metal reinforcing ribseach having a U cross-section, the arms of the U being adhered toadjacent longitudinally extending marginal areas of adjacent channels,the contained angle of the cross-section of said tray at said adjacentlongitudinally extending areas being less than 90*, said contained angleof a cross-section of said tray at the longitudinally extending areasbeing 45*, plus or minus 10*, and transverse reinforcing ribs adhered toand complementary to the cross-sectional shape of said bottom.